Fan and fan housing thereof having flapper

ABSTRACT

A fan includes a motor base, a motor, an impeller, and a fan housing. The fan housing accommodates the motor base, the impeller, and the motor, and includes at least one flapper disposed at the corner of the fan housing via a plurality of connecting elements for covering the opening of the fan housing to prevent the air backflow.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No. 11/907,363, filed on Oct. 11, 2007, and claims priority to Taiwan Application Serial Number 095147374, filed on Dec. 18, 2006, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a fan and a fan housing thereof, and, in particular, to a fan and a fan housing having a flapper.

2. Related Art

The computer system has become more complex, so the fans used in the computer system have to provide more efficient heat-dissipating ability. If one of the fans malfunctions while the computer system is operating, a backflow through the fan occurs since the interior of the computer system has negative pressure. The backflow will affect the airflow in the computer system and thus decrease the heat-dissipating ability of the fans. The prior art provides several flappers disposed on the outlet of the fan frame to prevent the backflow problem. As shown in FIG. 1, a conventional anti-backflow fan 1 includes a fan body 11 and a fan frame 12. The fan body 11 is disposed inside the fan frame 12. Generally speaking, the fan body 11 has an impeller and a motor (not shown). The motor rotates the impeller to produce the airflow direction A as indicated in FIG. 1. The fan frame 12 is used to protect the fan body 11 and provide some fixing parts so that the magnetic conduction coils and circuit board of the motor can be disposed in the fan frame 12. Moreover, the fan frame 12 usually has several installation holes 121 for the user to fix the fan 1 on systems.

To prevent the airflow from leaking out of the outlet 13 of the fan 1 when the fan 1 becomes ineffective or non-operating, an anti-backflow device 14 is usually disposed on the outlet 13 to stabilize the airflow field therein. In this case, the airflow is forbidden to enter the system via the outlet 13.

The anti-backflow device 14 has a frame 141 and several flappers 142. The frame 141 is connected and fixed on the fan frame 12 by using the installation holes 121. The flappers 142 are pivotally installed on the frame 141 and cover the outlet 13. When the fan 1 operates, the airflow passes through the outlet 13, pushes the flappers 142 and then goes out. When the fan 1 stops operating, the flappers 142 cover the outlet 13 to prevent backflows. However, although the anti-backflow device 14 can avoid backflows and thus stabilize the airflow field inside the system, the anti-backflow device 14 often uses the installation holes 121 of the fan 1 to connect to the fan frame 12. In that case, the installation holes 121 are not allowable for the user to use. The use of the fan 1 is thus limited. In addition, the anti-backflow device 14 and the fan frame 12 are two separate pieces. Not only are they likely to depart from each other, it also takes more production cost and time.

Therefore, it is an important subject to provide a fan and fan housing with a flapper that can improve the design and efficiency of the conventional structure, thereby maintaining the heat-dissipating efficiency of the fans and decreasing the manufacturing cost and installation space.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a fan and fan housing with a flapper that can prevent the backflow problem caused by the negative pressure inside the computer system while the fan malfunctions. Moreover, the heat-dissipating efficiency of the fans can be maintained, and the manufacturing cost and installation space can be decreased.

To achieve the above purpose, the invention discloses a fan housing with an opening, a motor base, and a flapper. The flapper is disposed at an outlet side of the fan housing via a plurality of connecting elements. The connecting elements respectively connect the flappers to a corner of the fan housing. The flappers cover the airflow passage of the fan housing when the fan malfunctions or stops.

To achieve the above object, the invention also discloses a fan including a motor base, a motor, an impeller with a plurality of blades, and a fan housing. The motor is disposed on the motor base for driving the impeller to rotate. The fan housing accommodates the motor base, the impeller with a plurality of blades and the motor. The fan housing includes at least one flappers disposed at an outlet side of the fan housing and pivotally coupled to the fan housing via a plurality of connecting elements. The connecting elements respectively connect the flappers to a corner of the fan housing. The flappers cover the airflow passage of the fan housing without covering the motor base when the fan malfunctions or stops.

As mentioned above, the flapper of the invention is connected to the corner of the fan housing. Thus, the flapper is directly coupled to the fan housing, so that the fan housing does not occupy additional space, the additional elements for installing or fixing the flapper are unnecessary, and the structure and manufacturing of the fan housing are simplified. Compared with the prior art, the invention modifies the corner of the fan housing adjacent to the outlet and the other parts of the fan housing are remained. In the invention, the flapper can be closed by the negative pressure inside the computer system. Thus, the position and direction of the fan installed in the system are not limited, and the flapper can be closed. Accordingly, the heat-dissipating efficiency of the fans can be maintained, and the manufacturing cost and installation space can be decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 is a schematic illustration of a conventional fan;

FIG. 2 is an exploded view of a fan according to the first embodiment of the present invention;

FIG. 3 is a perspective view of the fan of FIG. 2 after being assembled;

FIG. 4 is a schematic illustration showing that grooves are formed to restrict the maximum strokes of the flappers of the fan of FIG. 2;

FIG. 5 is a perspective view of a fan when the flappers are opened according to the second embodiment of the present invention;

FIG. 6 is a perspective view of the fan of FIG. 2 when the flappers are closed;

FIG. 7 is an enlarged view of the part A of FIG. 5; and

FIG. 8 is an enlarged view of the part B of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

As shown in FIG. 2, a fan 2 includes a fan housing 21 with an opening 2111 and a motor base 22 connected to the fan housing 21 via guiding vanes 23. The fan housing 21 has two supporting parts 2112 are provided on two opposite sides of the opening 2111 and several fixing parts 2113 symmetrically disposed on the supporting parts 2112. The fan housing 21 further comprises at least one flapper 212 respectively pivoted on the fixing parts 2113 formed on the fan housing 21 for covering an opening 2111 at the outlet side of the fan housing 21.

As shown in FIG. 3, the arrows A show the airflow direction, and the flappers 212 are directly pivotally installed on the fixing parts 2113 to cover the opening 2111. When the airflow passes through the opening 2111, the flappers 212 rotate around the fixing parts 2113. When no airflow passes through the opening 2111, the flappers 212 return to the original positions to cover the opening 2111 due to gravity or pressure difference.

In order to prevent the flappers 212 from exceeding a maximum stroke and being unable to return to their original positions, several stopping elements 2114 are provided at the supporting parts 2112 to restrict their maximum strokes. In this embodiment, the stopping element 2114 is a protruding part connected to the corresponding supporting part 2112. The stopping elements 2114, the fan housing 21 and the fixing parts 2113 can also be formed as a single unit. When there is airflow, the flappers 212 reach their maximum strokes and are blocked by the stopping elements 2114. Therefore, when there is no airflow, the flappers 212 can go back to their original positions under the influence of gravity or pressure difference.

Please refer to FIG. 4. Another way to restrict the maximum strokes of the flappers 212 is to form a groove 2115 on the fixing parts 2113. A protruding element 2121 is then provided on the flappers 212 corresponding to the groove 2115. By requiring the protruding element 2121 to move within the groove 2115, the maximum stroke of each flapper 212 can be limited by the length of the groove 2115.

The fan housing 21 has several installation holes 2116 for the user to fix the fan 2 onto a system. Since the flappers 212 are pivotally installed on the fixing parts 2113 directly, the installation holes 2116 can be preserved for the user to use.

With reference to FIGS. 5 and 7 showing the second embodiment of a fan 3 according to the present invention. The fan 3 includes a motor base 22, an impeller with a plurality of blades 41 (not shown), a motor (not shown) and a fan housing 21. The fan 3 can be an axial-flow fan or a centrifugal fan. The fan 3 is similar to fan 2 as above described except that each of the flappers 321 is pivotally connected to a corner of the fan housing 21 via the connecting element 322, and the shape of the flappers 321 corresponds to the shape of the opening 2111 without covering the motor base 22 when the fan 3 malfunctions or stops. The flapper 321 is connected to a corner of the fan housing 21 by the way of, for example but not limited to, pivoting, locking, clipping or wedging.

The flapper 321 can be also connected to the nearby fixing aperture 316 at the four corners of the fan housing 21. The fan housing 21 further comprises a cylindrical portion 213 and an outwardly expanding portion 214, and the guiding vanes 23 are connected between the motor base 40 and the cylindrical portion 213. In another embodiment, the flappers 321 can also have a protruding element and the fan housing 21 comprising a groove formed on an inner wall of the fan housing 21 corresponding to the protruding element.

The fan 3 is installed in a computer system. If the fan 3 operates normally, the flappers 321 are opened toward an outlet direction by rotating the connecting element 322. If the fan 3 malfunctions or stops and the other fans still operate normally, which cause a negative pressure, the flappers 321 will be closed to cover the airflow passage of the fan housing 21 without covering the motor base 22 (as shown in FIG. 6) to prevent the backflow. Therefore, the heat-dissipating efficiency of the fans in the computer system can be maintained. In addition, the flapper 321 is positioned at the same plane of the opening of the fan housing 21 without protruding out of the fan housing 21.

Referring to FIG. 8, the fan housing 21 further includes a plurality of restricting elements 215 disposed adjacent to the connecting elements 322, respectively, or to the corner of the fan housing 21 for restricting a maximum open angle of the flappers 321. In the embodiment, the maximum open angle is, for example but not limited to, 90 degrees. The restricting element 312, the connecting element 322, and the flappers 321 can be integrally formed as a single unit. Alternatively, the restricting element 312 can be integrally formed on the corner of the fan housing 21. When the fan 3 operates and the flappers 321 is opened toward the outlet direction by rotating the connecting element 322, the restricting element 312 can restrict a maximum open angle of the flapper 321, which is smaller than 90 degrees. Therefore, the problem that the flappers 321 cannot be closed by the negative pressure inside the computer system due to the exceeding open angle can be avoided.

In summary, the fan of the present invention has the flappers connected to the corner of the fan housing. Thus, the fan housing does not occupy additional space, the additional elements for installing or fixing the flappers are unnecessary, and the structure and manufacturing of the fan housing are simplified. Furthermore, the design of the flappers can only cover the airflow passage and does not cover the motor base when the fan malfunctions or stops. Compared with the prior art, the invention modifies the corner of the fan housing adjacent to the outlet and the other parts of the fan housing are remained. In the invention, the flappers can be closed to cover the airflow passage of the fan housing without covering the motor base by the negative pressure inside the computer system. Thus, the position and direction of the fan installed in the system are not limited, and the flappers can be closed. Accordingly, the heat-dissipating efficiency of the fans can be maintained, and the manufacturing cost and installation space can be decreased.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention. 

1. A fan comprising: a fan housing with an opening; a motor base disposed in the fan housing; and at least one flapper pivotally coupled to a corner of the fan housing for covering the opening.
 2. The fan according to claim 1, wherein the flapper is connected to the fan housing via at least one connecting element.
 3. The fan according to claim 1, wherein the flapper is disposed at an outlet side of the fan housing corresponding to a peripheral edge of the motor base.
 4. The fan according to claim 1, wherein the fan housing further comprises a cylindrical portion and an outwardly expanding portion, and the motor base is connected to the cylindrical portion via a plurality of guiding vanes.
 5. The fan according to claim 1, wherein the flapper is connected to a nearby fixing aperture at the corner of the fan housing.
 6. The fan according to claim 2, further comprising a plurality of restricting elements disposed adjacent to the connecting elements.
 7. The fan according to claim 6, wherein the restricting element and the connecting element are integrally formed as a single unit.
 8. The fan according to claim 6, wherein the restricting element is integrally formed on the corner of the fan housing.
 9. The fan according to claim 2, wherein the flapper and the connecting element are integrally formed as a single unit.
 10. The fan according to claim 1, wherein the maximum open angle of the flapper is smaller than or equal to 90 degrees.
 11. The fan according to claim 1, wherein the flapper is connected to the corner of the fan housing by pivoting, locking, clipping or wedging.
 12. The fan according to claim 1, wherein the fan is an axial flow fan or a centrifugal fan.
 13. The fan according to claim 1, wherein the flapper is positioned at the same plane of the opening of the fan housing without protruding out of the fan housing.
 14. The fan according to claim 1, wherein the flapper has a protruding element and the fan housing comprises a groove formed on an inner wall of the fan housing corresponding to the protruding element. 